/*
 * Copyright (c) 2014-2022 Monix Contributors.
 * See the project homepage at: https://monix.io
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package monix.reactive.internal.operators

import monix.execution.Cancelable
import monix.execution.cancelables.OrderedCancelable
import monix.reactive.Observable
import monix.reactive.observers.Subscriber
import scala.concurrent.duration.FiniteDuration

private[reactive] final class DelayExecutionByTimespanObservable[A](source: Observable[A], timespan: FiniteDuration)
  extends Observable[A] { self =>

  def unsafeSubscribeFn(out: Subscriber[A]): Cancelable = {
    val conn = OrderedCancelable()
    val main = out.scheduler.scheduleOnce(
      timespan.length,
      timespan.unit,
      () => {
        conn.orderedUpdate(source.unsafeSubscribeFn(out), order = 2)
        ()
      }
    )

    conn.orderedUpdate(main, order = 1)
  }
}
